模拟降水条件下生物炭对酸性红壤理化性质的影响

【目的】明确降水条件下生物炭对红壤理化性状的影响。【方法】采用室内模拟降水的方法，将以花生壳为原料在400℃热解制备的生物炭施入红壤，在气温25-30℃、单次降水量20 mm条件下进行连续试验约20 d，分析生物炭对施肥和未施肥红壤的速效钾（SAK）、速效磷（SAP）、铵态氮（SAN）、硝态氮（SAN）、有机碳（SOC）、活性铝（SAA）以及pH值在降水前后的变化。共设8个试验处理：未施肥+未施C（CK）、未施肥+1%生物炭（C1）、未施肥+2%生物炭（C2）、未施肥+3%生物炭（C3）；施肥+未施C（F）、施肥+1%生物炭（FC1）、施肥+2%生物炭（FC2）、施肥+3%生物炭（FC3）。施肥土壤施用KH₂PO₄ 0.14 g·kg^-1、KNO₃ 0.51 g·kg^-1、NH₄NO₃ 0.80 g·kg^-1和Ca(NO₃)₂ 0.95 g·kg^-1。【结果】施用生物炭的红壤，其速效钾、速效磷、硝态氮、铵态氮、活性铝、有机质和pH等指标在降水后均有较大变化，且不同生物炭用量对红壤理化性质的影响存在较大差异。施用3%生物炭时，土壤理化性质在降水前后变化最为显著，C3处理的pH值比CK处理提高了0.60个单位，速效钾的下降幅度比CK少9.5%，速效磷、硝态氮的下降幅度分别比CK高出33.2%和40.5%，有机碳和铵态氮则没有明显变化，活性铝下降了91.1%。而降水后FC3处理的pH值比F处理提高了1.09个单位，速效钾的下降幅度比对照少10.3%，速效磷和硝态氮的下降幅度分别比F处理高23.4%和21.9%，有机碳和铵态氮的增幅分别比F处理高23.6%和5.4%，活性铝下降了94.8%。【结论】在降水条件下，生物炭有利于酸性红壤保持适宜的速效钾含量，提高土壤pH值和有机碳含量，以及能大幅降低土壤活性铝浓度，且对施肥后酸性红壤理化性质的影响更明显。

Effects of Biochar on Physico-Chemical Properties of Acid Red Soil Under Simulated Rainfall Condition

【Objective】 Purposes of this study are to determine if biochar has effects on red soil under precipitation conditions, and the difference between no-fertilization soil and fertilization soil.【Method】A rainfall simulation experiment was carried out with different biochar levels (biochar/soil: 0%, 1%, 2% and 3%) on red soil, and some characters such as soil available phosphorus (SAP), available potassium (SAK), nitrate nitrogen (SNN), ammonium nitrogen (SAN), organic carbon (SOC) and active aluminum (SAA) were determined.【Result】Under precipitation conditions, the variation of SAN, SOC, SAA and pH in red soil was observably. When 3% biochar was added, the change of soil characters was most significantly. Compared with the no-fertilization control (CK), soil pH raised by 0.60, SAA decreased by 91.1%, the descent range of SAK decreased by 9.5%, the descent ranges of SAP and SNN, respectively, increased by 33.2%, 40.5% in no-fertilization soil with 3% biochar application. Compared with the fertilization control (F), soil pH raised by 1.09, SAA decreased by 94.8%, the descent range of SAK decreased by10.3%, the descent ranges of SAP and SNN, respectively, increased by 23.4% and 21.9%, SOC and SAN, respectively, increased by 23.6% and 5.4% in fertilization soil with 3% biochar application rate.【Conclusion】Under precipitation conditions, biochar was propitious to maintain SAP, improved soil pH and SOC, and decreased SAA, especially in red soil with fertilizer application.